N-methyl-D,L-aspartate acid and bicuculline are required to enhance the trigeminal rhythmic activities in an in vitro isolated brainstem block preparation. In this study, we analyzed the effect of norepinephrine on the trigeminal neural circuit underlying rhythmic jaw movements. Rhythmic trigeminal activity is observed in brainstem preparations (inferior colliculus to obex) only following blockade of α2-adrenoceptors with idazoxan. This observation, combined with the inhibition of rhythm by α2-adrenoceptor agonists suggests endogenous α2-adrenoceptor mediated inhibition of trigeminal networks. A complex noradrenergic modulation of trigeminal systems is further supported by the prazosin-sensitive potentiation of rhythm by bath application of the α1-adrenoceptor agonist phenylephrine. Copyright (C) 2000 Elsevier Science Inc.
- In vitro brainstem preparation
- Rhythm generation
- Trigeminal motor activity
ASJC Scopus subject areas